The present invention relates to automatic control apparatus such as TV camera auto setup systems, and particularly sets forth a TV camera setup system permitting manual readjustment of automatically established settings.
State of the art television cameras, particularly color television cameras, are highly complex instruments having an elaborate array of controls which must be critically adjusted in order for the camera to operate satisfactorily. Correctly adjusting (or "setting up") the camera is a prodigious and time consuming task requiring substantial skill, experience, and patience. Camera setup is emminently well-suited for automation, and indeed recently there have appeared automatic setup systems for TV cameras. These automatic setup systems utilize microprocessors for monitoring the video signals provided by the TV camera and for automatically establishing the proper setup adjustments in response thereto.
Such automatic setup systems adjust the settings to arrive at those settings which produce the best overall picture. In specific instances it may be desirable to adjust the controls differently, however. More specifically, an automatic registration setup system is generally designed to adjust the registration so that the best registration is found near the center of the subsequently displayed picture. This is because normally the viewers attention is directed toward the center of the screen. In certain instances, for example during the taping of commercials, it may be desirable to achieve best registration at a point on the screen other than the center. It may similarly be desirable to change other settings established by the automatic setup system to conform with the needs of the specific use of the camera.
One known automatic setup system includes manual controls in addition to the automatic setup system. The output of each of the manually adjustable controls is combined with the corresponding output of the automatic setup system so as to provide a control signal which is adjustable both manually and automatically. A difficulty with this approach is that the manual controls are continually coupled in with the automatic setup controls. The manual control signals are therefore included within the closed loop of the automatic setup system during automatic setup of the TV camera. Consequently, for proper operation the manual controls must be centered before the auto setup operation takes place. Restriction of the range of manual variation could occur if one of the manual controls were set near one of its operating limits during the automatic setup operation, since the auto setup system will "adjust out" the manual signal during auto setup.